package buildstep

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"
)

// 1887/A7: the node's build capacity is the build module's setting, read at every pull: the control-node at 0 pulls
// nothing, a change takes effect at the next read, and a setting that cannot be read pulls nothing.
// ADR 0553 §4: a step's threads are the composer's share over the module's own capacity; without the word, none. And
// issue 1806's follow-up: the capacity judged by is the configured one bounded by the build slice's cores over the cores
// a step needs (the three build nodes as they stand on 2026-10-26), and cores-per-step is read from the settings file.
func TestNodeCapacityAndLimits(t *testing.T) {
	// ADR 0567 §12: the capacity is the node's integer, its default 0, and no default names a node.
	if got := NodeCapacity("", "laptop", nil)(); got != 0 {
		t.Errorf("no settings file = %d, want 0", got)
	}
	file := filepath.Join(t.TempDir(), "settings.json")
	capacity := NodeCapacity(file, "anchor", nil)
	for value, want := range map[string]int{`{"capacity":1}`: 1, `{"capacity":4}`: 4, `{}`: 0, `{"capacity":null}`: 0,
		`{"capacity":"anchor=3"}`: 0, `{"capacity":-1}`: 0, `{"capacity":1.5}`: 0} {
		os.WriteFile(file, []byte(value), 0o600)
		if got := capacity(); got != want {
			t.Errorf("%s = %d, want %d", value, got, want)
		}
	}
	if got := NodeCapacity(filepath.Join(t.TempDir(), "none"), "anchor", nil)(); got != 0 {
		t.Errorf("a missing file = %d, want 0", got)
	}
	t.Setenv("MESH_BUILD_CPU_SHARE", "")
	if l := NodeLimits(3); l.Threads != 0 || l.Slots != 3 {
		t.Errorf("without the word: %+v", l)
	}
	t.Setenv("MESH_BUILD_CPU_SHARE", "75")
	if l := NodeLimits(3); l.Percent != 75 || l.Slots != 3 || l.Threads < 1 {
		t.Errorf("from the word: %+v", l)
	}
	for _, c := range []struct {
		name              string
		configured, quota int
		cores             float64
		effective, byCPU  int
	}{
		{"shanks: 12 cores, configured 3", 3, 1200, 6, 2, 2},
		{"ace: 18 cores, configured 2", 2, 1800, 6, 2, 3},
		{"g14: 8 cores, configured 2", 2, 800, 6, 1, 1},
		{"node on shanks: 12 cores at 2", 3, 1200, 2, 3, 6},
		{"no quota: the configured one", 3, 0, 6, 3, 0},
		{"configured 0 pulls nothing", 0, 1200, 6, 0, 0},
		{"a quota under one step still builds one", 2, 100, 6, 1, 1},
		{"no cores a step is one", 2, 150, 0, 1, 1},
	} {
		got := EffectiveCapacity(c.configured, c.quota, "test", c.cores)
		if got.Effective != c.effective || got.ByCPU != c.byCPU || got.Why == "" {
			t.Errorf("%s: %+v, want effective %d, by CPU %d", c.name, got, c.effective, c.byCPU)
		}
	}
	file = filepath.Join(t.TempDir(), "settings.json")
	var said []string
	cores := NodeCoresPerStep(file, 6, func(f string, a ...any) { said = append(said, f) })
	for _, c := range []struct {
		file string
		want float64
	}{{`{"capacity":2}`, 6}, {`{"cores-per-step":4}`, 4}, {`{"cores-per-step":"3.5"}`, 3.5}, {`{"cores-per-step":0}`, 6}, {`{"cores-per-step":0}`, 6}} {
		os.WriteFile(file, []byte(c.file), 0o600)
		if got := cores(); got != c.want {
			t.Errorf("cores-per-step from %s = %g, want %g", c.file, got, c.want)
		}
	}
	if len(said) != 1 {
		t.Errorf("a value not above zero is said once, said %d times", len(said))
	}

	// The operator, 2026-10-26 21:18: g14 builds only from 18:00 to 06:00, its local time. Outside its build hours the
	// capacity judged by is 0, said with the window and when it opens; a node not named, or a bad value, builds at any hour.
	// And a node its module proves cannot build (ace without /dev/net/tun, 2026-10-28) judges by 0 at every hour, saying
	// why, so its asks go to a node that can.
	cet := time.FixedZone("CET", 3600)
	day := func(hh, mm int) time.Time { return time.Date(2026, 10, 26, hh, mm, 0, 0, cet) }
	was := now
	defer func() { now = was }()
	for _, c := range []struct {
		name, setting, node string
		at                  time.Time
		effective           int
		edge                string // the window's next edge, HH:MM; "" for no window
		bad                 bool
		ineligible          string // what the module's Eligible says; "" for eligible
	}{
		{"the laptop in the office", "18:00-06:00", "laptop", day(10, 0), 0, "18:00", false, ""},
		{"the laptop in the evening", "18:00-06:00", "laptop", day(18, 0), 2, "06:00", false, ""},
		{"the laptop past midnight", "18:00-06:00", "laptop", day(5, 59), 2, "06:00", false, ""},
		{"the laptop at the close", "18:00-06:00", "laptop", day(6, 0), 0, "18:00", false, ""},
		{"a day window", "09:00-17:30", "anchor", day(17, 29), 2, "17:30", false, ""},
		{"no window", "", "anchor", day(10, 0), 2, "", false, ""},
		{"a bad time", "18:00-6", "laptop", day(10, 0), 2, "", true, ""},
		{"no span", "18:00-18:00", "laptop", day(10, 0), 2, "", true, ""},
		{"the old form naming a node", "laptop=18:00-06:00", "laptop", day(10, 0), 2, "", true, ""},
		{"a node without /dev/net/tun", "", "anchor", day(10, 0), 0, "", false, "/dev/net/tun cannot be opened: no such device"},
		{"not eligible within its hours", "18:00-06:00", "laptop", day(19, 0), 0, "06:00", false, "/dev/net/tun cannot be opened: no such device"},
	} {
		w, err := ParseBuildWindow(c.setting)
		if (err != nil) != c.bad {
			t.Errorf("%s: parse %v", c.name, err)
		}
		if edge := ""; w != nil {
			edge = w.NextEdge(c.at).Format("15:04")
			if edge != c.edge {
				t.Errorf("%s: next edge %s, want %s", c.name, edge, c.edge)
			}
		} else if c.edge != "" {
			t.Errorf("%s: no window, want one", c.name)
		}
		file := filepath.Join(t.TempDir(), "settings.json")
		os.WriteFile(file, []byte(`{"build-hours":"`+c.setting+`"}`), 0o600)
		now = func() time.Time { return c.at }
		p := &Puller{Language: "go", Node: c.node, Capacity: func() int { return 2 }, BuildHours: NodeBuildHours(file, c.node, nil),
			Eligible: func() string { return c.ineligible }}
		got := p.CapacityDetail()
		outside := c.effective == 0 && c.ineligible == ""
		if got.Effective != c.effective || got.OutsideHours != outside || (outside && !strings.Contains(got.Why, "outside its build hours 18:00-06:00 CET until 18:00")) {
			t.Errorf("%s: %+v, want capacity %d", c.name, got, c.effective)
		}
		if got.Ineligible != c.ineligible || (c.ineligible != "" && !strings.HasPrefix(got.Why, "0, not eligible: "+c.ineligible+" (otherwise ")) {
			t.Errorf("%s: not eligible is not said: %+v", c.name, got)
		}
		// A value that cannot be read builds at any hour, loudly: the record names the value and says why.
		if c.bad && (!strings.Contains(got.BuildHoursFault, c.setting) || !strings.Contains(got.Why, "at any hour, because its build hours cannot be read")) {
			t.Errorf("%s: a bad value is not said in the record: %+v", c.name, got)
		}
	}
}